Keyboard Shortcuts
ctrl + shift + ? :
Show all keyboard shortcuts
ctrl + g :
Navigate to a group
ctrl + shift + f :
Find
ctrl + / :
Quick actions
esc to dismiss
Likes
Search
Re: Losmandy Polar scope calibration
|
Celestron has a polar scope alignment "how to" that will work with any polar scope. I like it because celestron breaks it down to simple steps with graphics. https://www.google.com/url?sa=t&source=web&rct=j&url=https://s3.amazonaws.com/celestron-site-support-files/support_files/1223669429_polaraxixfinder.pdf&ved=2ahUKEwjD8rGrqI3vAhUMQK0KHcwHCNoQFjAAegQIARAC&usg=AOvVaw076vH0ziID6s_0497-n6xC It's a pdf file Chuck On Sunday, February 28, 2021, 11:22:44 AM PST, Michael Herman <mherman346@...> wrote: Hi Bob, All these optical polar scopes have a moveable glass reticle (also spelled reticule) that is centered (you must do this centering optically) with 3 tiny setscrews. Sometimes the setscrews have a flat screwdriver slot, and sometimes they have a tiny allen head.?? First thing to do is focussing the optical parts: First focus the eyepiece on the reticle markings. Then unlock and screw in and out the long barrel at the end of the polar scope, until a star (or very far object like a distant treetop) is in focus. When done, both the reticle and the faraway object are both in focus for your vision.?? Next thing to do is adjust the reticle position... The key thing to know is that the reticule is glass and can be cracked...instantly... by too much pressure from the metal setscrew.? So you must back out one setscrew before you tighten down another one.? It is very tedious?to do this ... like adjusting the secondary mirror of an SCT which is a similar iterative process.?? You point your RA at a convenient target like a faraway treetop, in the daytime.? You rotate the RA axis and watch the "+" symbol that is the center of the reticle markings.? You watch that "+" symbol move.? You want to adjust the reticle position with the 3 setscrews?until you about center the "+" sign as best as possible when the RA axis rotates.? I put the?+ sign on the top of the tree when the tree image is focussed. Now here's the rub:? It is often observed that if you loosen the front locking round black disk that holds on the polar scope... and you rotate the polar scope, that the?+ sign will no longer be centered!? This is the common observation.? This means you want to keep that polar scope in its place on the RA of the mount, or at least mark its orientation with some method (white labelmaker?tape cut in triangles works for me.)? ?But this is not the way the Losmandy polar scope is supposed to work...it is supposed to be rotated to line up Cassiopeia?or the Big Dipper and a few stars near polaris.? So... you must judge what to do. There is a website with info about this polar scope, but it lacks the details about about practical matters.?? The better approach is to get a Polemaster electronic imaging pole camera and lens. This works very nicely, and saves your back and eyeballs.? But it is not free...naturally.? ? All the best, Michael On Sun, Feb 28, 2021 at 11:05 AM TeleGizmos <sales@...> wrote: Just received my GM811G, assembly complete, went quite well. Installed and checked the polar scope alignment and it's a bit out of calibration to the mount. Question is for visual observing only, how critical is spot on polar scope calibration to the mount? I know how perform calibration on a polar scope but have never bothered to concern myself with this in the past. However, this is the first mount I've owned that is go-to and want the go-to to be accurate. --
|
to navigate to use esc to dismiss